Automatic data collection is used in many sectors of our economy. In many applications, data collection devices such as bar code scanners or radio frequency interrogators are connected to a host or client computer system that processes the data they collect. Some data collection devices communicate through a wired interface. Other models may be used in a store-and-forward or batch mode. Still others interface to the host or client computer via a wireless interface such as a radio or infrared interface.
While there are many choices of interfaces available to the user, they are often not interchangeable. For example, if a user wishes to have a bar code scanner with a radio interface, that scanner may not operate or may not be convenient to operate in a directly connected wired mode.
In other cases, if a user wishes to have an option of using various interfaces in the future, it may be necessary to purchase a more expensive scanner than might otherwise be required or else purchase a completely new scanner to make such a change. For example, if a user purchases a portable scanner in a batch mode, collecting data for subsequent upload to a host or client system, but later decides it best to operate in a wireless mode, it is frequently necessary to purchase a completely new scanner, thus effectively losing the original investment in the batch scanner.
In some cases, adapters may be available for adding a new interface. In particular, there are some third-party radios that a wired-interface data collection device may be connected to add a wireless interface. Unfortunately, such adapters are frequently bulky or ungainly so as to harm the ergonomics of the data collection device. In addition, there may be problems with interface reliability when switching between interface modes. For example, a third-party radio adaptor may be prone to dropping messages, a flaw that may be quite significant in many applications.
With data collection devices and other portable electronic devices that do have a radio interface, there may be shortcomings in operation that adversely affect the use experience. For example, it is frequently inconvenient to add devices, change end device to host pairing, and un-pair devices for use with a different host. Other systems suffer from the inconvenience of dropping and not restarting communication sessions when the end device temporarily moves out of radio range. Still other systems, consume more power than is optimum by staying in a “sniff” or other mode for long periods of time when there is no data transmitted. Other systems may suffer from end devices that re-pair with the wrong host rather than making a strong enough connection to the intended host to prevent such a possibility.
Several radio interface standards are available for use with portable electronic devices. These include spread-spectrum radio standards that are especially immune to interference and may be used in unlicensed environments. These include IEEE 802.11a, 802.11b, 802.11g, and Bluetooth™. The book entitled, “Bluetooth™ Connect Without Cables”, by Jennifer Bray and Charles F. Sturman, published by Prentice Hall PTR, 2001, hereby incorporated by reference, contains information useful for understanding radio data interfaces, and particularly Bluetooth.